The present disclosure relates to semiconductor processing methods, and particularly to methods for high fidelity patterning employing a high density plasma, and structures for effecting the same.
Pattern transfer at small dimensions and small pitch solutions requires high precision. A typical phenomenon for pattern transfer at small dimension is the deformation of the patterning materials as a result of plasma processing. The deformation typically occurs when a mask in a soft (carbon-based) material is transferred into a harder material (such as a semiconductor material, silicon oxide, silicon nitride, silicon oxynitride, and metallic materials).
The deformation of the pattern is known to originate from substantial modification of the soft material by the plasma that eventually leads to mechanical failure of the soft material. In particular, interaction of a plasma polymer with a soft patterning material can cause substantial problems.
Proposed solutions to this problem include use of novel patterning materials or use of hardening processes. Suitable novel patterning materials capable of a high fidelity pattern transfer are difficult to identify. Hardening processes require treatment at elevated temperatures, which can adversely impact device performance due to the undesirable effect of additional thermal cycling on device performance. A novel approach has also been proposed in which alternative patterning materials having stoichiometries tailored to reduce the occurrence of the phenomenon of pattern deformation are employed.